US2495317A - Harmonics generator - Google Patents

Description

Jan. 24, 1950 DORBEC 2,495,317

HARMONICS GENERATOR Filed May 21, 1946 5 L w 4 [I 10 V T Tl/ll/[D C/lfCU/T Patented Jan. 24, 1950 HARMQNIES GENERATOR Lucien D'orliec, Paris, France, assignor to, So.-

ciete Anonyme de Telecommunications; France, a body corporate (if-France Application-May '21, 1946;,Seria-l Noc671,187 IntFrance August 6, 19,42

4 Claims'. (Cl,..2'503,6)

The present invention relates: tos a, harmonics" generator or to a frequency: multinlie'n harmonics generator has for its object to enable the complete seriesof successive harmonics or odd harmonics only to be produced at will, and,

according as it is desired to producethe complete series of successive harmonics; or odd harmonics only and meansfor. returningyto-the input-circult of said modulator part;- of." the product-{of modulation.

A form of embodiment"of'theharmonics generatoraccording to the invention is hereinafter described and. illustrated in; the. accompanying drawing, by way of example.

The fundamental frequency of which it is desired to produce harmonics, supplies the transformer I, the secondary of which is connected to the apices of one of the diagonals of a circuit in the form of a balanced bridge the four arms of which each contain a rectifier 2, 2, 3, 3 for example a metal-oxide rectifier. The other diagonal has its apices connected to the primary of the transformer 4 in the secondary of which the required harmonics are collected. It is known that I being the frequency of the current supplying the input transformer I, if a source of frequency F is connected to the mid points 5 and 6 of the windings 1, 8 of the two transformers which are connected to the bridge 2, 2', 3, 3', the double symmetry of the circuit thus produced results in the beat frequencies, F-f and F+f alone appearing in the output circuit, to the exclusion of the frequencies F and f. If then, by means of a reaction circuit, part of the products of the modulation received in the output transformer 4 is returned into the primary of the input transformer I, it will readily be seen that:

1. If F=f, the frequencies f, 2 3f nf, that is, the complete series of successive harmonics will be obtained, by successive beats in the modulator.

2. If F=2f, the series of odd harmonics f, 3,, 5f (2n+1)f will be obtained under the same conditions.

The circuit according to the invention applies the method explained above and it consists, on the one hand, in connecting the circuit supplying the transformer I with the fundamental frequency to the midpoints 5, B of the windings I, 8 of both transformers connected to the balanced bridge. 2;, .25, 3;. .35 through: themedium. of 1a frequencydoublingqdevicer 9fai'so constituted; for: example, by arectifieri' circuiti arranged in: the form on a bridgeazand-g. if! necessary; through the mediumrofi'ar filter [3, thefrequency'doubli'ng device being: used atr'will or; put out ofi'circuit, by means of: a switch, l4; according-as itiisd'esired to obtainpoddeharmon-icsxorthe complete series of the successive harmonics in the output transformer tithe points 6: being, in this latter: case, direct 1yconnectedto:thexprlmary of the transformer I. 0n, the: other hand, the primary of the trans former 4 is: coupled, for example by induction, to; the secondary of the transformer l in order tolretumi totthelatterwpart of the current modulated in 2', 2-, 3, 3".'. To-this end, an inductive winding l0, which is' arranged in the proximity of the primary of the transformer 4, is connected, for example through the medium of an amplifying vacuum tube II, to an inductive winding 12 arranged in the proximity of the input transformer I Under these conditions, the harmonic waves produced in the modulator due to the beat of the two oscillations applied to said modulator in parallel connection and in push-pull connection respectively, are in their turn applied through the feed back circuit in push-pull connection to the modulator in the same manner as the fundamental oscillation, giving rise to the production of a higher harmonic through the beat of the first named harmonic with the oscillation applied in parallel connection to the modulator and so on. According as the frequency applied in parallel connection to the modulator, i. e. at points 5 and 6, is equal or double of the fundamental frequency, a complete series of successive or odd harmonics will be thus obtained.

If the fundamental frequency is equal to 4,000 cycles per second, a frequency of 8,000 is introduced into the modulator through points 5, B, by making use of the frequency doubling device 9 and at the output end, frequencies of 12,000 and 4,000 will be obtained in the first place. After having passed these frequencies through the winding 1, by means of the reaction circuit III, II, l2, they give rise, by beats with the frequency.8,000, to a new frequency 20.000 which in its turn, after having reacted on the input circuit, produces a frequency 28,000, and so on for all the series of odd harmonics. On the contrary, by suppressing the frequency doubling device and by sending the frequency 4,000 both into the primary of the transformer I and to the 3 points 5, 6, all the successive harmonics are obtained.

In addition to its simplicity, the device in accordance with the invention oifers the advantage of enabling one of the harmonic frequencies to be produced by arranging a circuit I 5 tuned to the said frequency in the reaction circuit.

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What I claim is: 1. Harmonics generator for obtaining at will odd harmonics and the complete series of successive harmonics of a fundamental frequency,

comprising a symmetric modulator, means for supplying said modulator in push-pull connec-*" tion with the fundamental frequency, means for' 7 for by-passing said frequency doubling device and a positive feed-back circuit for coupling the supplying said modulator in parallel connection.

with the fundamental frequency, a frequency doubling device inserted in said last named conprimary of the output transformer to the secondary of the input transformer.

3. Harmonics generator according to claim 2 .,wherein the positive feed-back circuit comprises a winding coupled by induction with the primary of the output transformer, a second winding coupled by induction with the secondary of the input transformer and an amplifying tube c0nnect ing the said windings.

nection for doubling the fundamental frequency supplied in parallel connection to the modulator, means for by-passing said frequency doubling device and a positive feed back circuit connecting the output of the modulator to its input.

2. Harmonics generator enabling the odd harmonies and the complete series of successive harmonics of a fundamental frequency to be obtained, comprising a modulator constituted by a balanced bridge circuit, the four branches whereof each contain a rectifier, a source of fundamental frequency, an inputtransformer the primary of which is connected to said source whereas the secondary is connected to the apices of one of the bridge diagonals, an output transformer the primary of which is connected to the apices of the second bridge diagonal, whilst the mid-points of the secondary of the input transformer and of the primary of the output trans- 4. Harmonics generator according to claim 2 wherein the coupling between the output and the input of the modulator. comprises a circuit tuned to the frequency of a harmonic oscillation the production of which is particularly desired.

LUCIEN DORBEC.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,678,199 Rettenmeyer July 24, 1928 2,324,815 Black July 20, 1943 FOREIGN PATENTS Number Country Date 832,078 France Sept. 20, 1938

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